Home>Discussions>NEW DIY IDEAS>Home Technology>Does "Power-Save" really work?
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Fencepost
Re: Does "Power-Save" really work?
Fencepost

An intelligent discussion of watts, VA, power factor, etc. should only be attempted by a competent electrical engineer (or someone who has spent a significant time studying electrical principles). I do not fit into that category, so I will shy from the discussion.

The real questions are these: Will the device save more money during its useful life than the up-front costs of purchase and installation? and Will I be able to determine if it's really working as advertised?

Considering the second question, electricity usage in the home tends to be subjective and inconsistent. To perform a true test, you would have to use electrical appliances in your home in exactly the same, typical manner during two test periods, with and without the device attached. How in the world could you ensure those laboratory-like conditions?

Jack
Re: Does "Power-Save" really work?
Jack
Fencepost wrote:

An intelligent discussion of watts, VA, power factor, etc. should only be attempted by a competent electrical engineer (or someone who has spent a significant time studying electrical principles). I do not fit into that category, so I will shy from the discussion.

The real questions are these: Will the device save more money during its useful life than the up-front costs of purchase and installation? and Will I be able to determine if it's really working as advertised?

Considering the second question, electricity usage in the home tends to be subjective and inconsistent. To perform a true test, you would have to use electrical appliances in your home in exactly the same, typical manner during two test periods, with and without the device attached. How in the world could you ensure those laboratory-like conditions?

The original post, back in August, ask if it was a scam I answered no but qualified my answer because I had just received info on the unit and had not had time to fully research it. After further study though I have to say I believe it is a scam not because the unit doesn't do what they say but because it will not realize the savings for a homeowner that they suggest. Their suggestion that you can realize a 25% savings is not realistic for most home owners because most homeowners don't have enough of their electric used for inductive loads (primarily motors), which is on what the unit works. A large percentage of the average households electric use is for resistive loads (lights, heaters, stoves, ovens, water heaters, electronics, etc.) on which the unit will provide no savings.
Jack

Fencepost
Re: Does "Power-Save" really work?
Fencepost

Somebody in a previous post mentioned that many motors use capacitors and this is somehow supposed to correct for power factor.

As I understand it (and I doubt this is universal), most motors that have capacitors only use the capacitor during startup. The capacitor causes a lag (either current or voltage, I don't remember which) in one set of coils to provide extra starting torque and to get the motor spinning in the right direction. Once the motor reaches full speed, the capacitor is switched out of the circuit and the motor runs on induction only. I don't believe that the motor's capacitor plays any part in power factor correction.

islandmama
Re: Does "Power-Save" really work?
islandmama

Two questions for the group here.

1) Do these units provide any surge protection?

I live in a partially third-world territory of the U.S. and we have very dirty power (spikes and dips, extended brown-outs, etc.) that tends to greatly shorten the life of appliances, particularly expensive ones like refrigerators. We also have to rely on generator power for up to several weeks when storms knock out utilities, sometimes once per year. Do you think the Power-Save device would prove useful in these situations?

2) Someone here mentioned that Energy Star appliances don't benefit as much from the use of the Power-Save device. Why is that?

I was told by my friend who sells these devices that it would help protect my appliances from the dirty power from our utility. We do also have the mechanical meter that someone mentioned here.

Thank you for the input and I do appreciate any response!

Jack
Re: Does "Power-Save" really work?
Jack

1) Do these units provide any surge protection?

That will depend on the particular unit. Some come with MOV surge suppression but there are cheaper alternatives like http://www.homecontrols.com/cgi-bin/main/co_disp/displ/prrfnbr/1054/sesent/00/Leviton-Outdoor-Whole-House-Surge-Suppressor These units also don't produce electricity so they would have little if any on brownouts.

2) Someone here mentioned that Energy Star appliances don't benefit as much from the use of the Power-Save device. Why is that?

The more efficient a device is the less benefit you get from these units. The primary energy savings produced by these units is in power factor correction when running motors. They produce little or no savings in power used by resistive loads like lighting, water heaters,stoves etc. usually the biggest energy usage in a home.

Constant voltage transformers can correct brownout problems but have some significant short falls of their own. They tend to go into harmonic imbalance if there is a change in frequency which can easily occur when using a generator.

Whole house power conditioning and UPS units are available but are very expensive.
Jack

islandmama
Re: Does "Power-Save" really work?
islandmama

Thank you Jack!

I did call Power-Save yesterday and inquired about the surge protection; the 1200 unit offers 2000 joules of surge protection, which I understand in layman's terms to be: not enough to protect against damage from electrical storms, but sufficient to protect against typical surges from the utility company. Thanks for the link to the surge protector unit. Beyond that I will try asking my electrician if he has a product he likes. He's 83 years old so he may have seen what works and what doesn't.

I really hate having all those bulky surge protection power strips all over the house. They're ugly, they're not childproof, and they can add up to a good bit of $$.

MOV = Metal Oxide Varistor?

I think we are just going to have to grin and bear the dirty power until we can get most of our power from a solar system with batteries. I need to do a little more reading on how one achieves line conditioning in a grid-tied alternative energy system.

Does it help to protect items in the home from surges in a lighting storm to just run outside and throw the main breaker for the entire house?

I am getting off topic here, I guess I will search the forums for surge protection ideas!

Thanks again for your input and ideas!

JLMCDANIEL wrote:

1) Do these units provide any surge protection?

That will depend on the particular unit. Some come with MOV surge suppression but there are cheaper alternatives like http://www.homecontrols.com/cgi-bin/main/co_disp/displ/prrfnbr/1054/sesent/00/Leviton-Outdoor-Whole-House-Surge-Suppressor These units also don't produce electricity so they would have little if any on brownouts.

2) Someone here mentioned that Energy Star appliances don't benefit as much from the use of the Power-Save device. Why is that?

The more efficient a device is the less benefit you get from these units. The primary energy savings produced by these units is in power factor correction when running motors. They produce little or no savings in power used by resistive loads like lighting, water heaters,stoves etc. usually the biggest energy usage in a home.

Constant voltage transformers can correct brownout problems but have some significant short falls of their own. They tend to go into harmonic imbalance if there is a change in frequency which can easily occur when using a generator.

Whole house power conditioning and UPS units are available but are very expensive.
Jack

averagejim
Re: Does "Power-Save" really work?
averagejim

This thread has been a blast to read through. Very informative (and comical :D) thank you!

Re: Does "Power-Save" really work?

If every appliance in your house is 20 years old you may save 4 or 5% but considering every energy star appliance is manufactured with the same technology built in, its not worth the price in the typical home, tho some of these devices (not very familiar with this exact one) do offer some tvss protection and other benefits such as Harmonic Filtration, I would keep your money in your wallet for now. I do have a fealing that there may be more uses for these in the future tho... just a hunch.;)

BudX
Re: Does "Power-Save" really work?
BudX
ms0660 wrote:

I saw a commercial for a product called "Power-Save". It is basically a capacitor that you can install yourself on your main breaker box that is "supposed to" save you energy by storing electricity to help start motors such as Air conditioner compressors, refrigerators etc. Can you tell me if it is worth the investment of almost $300.00? It seems to me that your Microwave and your A/C compressors already come with its own capacitor. So Howcan this really help?....Is this a scam do you think?
Michael

For a residential user they are a scam.

Basically, in a motor during part of the AC cycle energy is goes into in a magnetic field, and during another part of the AC cycle comes back out (to the power grid). This causes a higher current than is needed to supply the mechanical load of the motor. Utility meters always *ignore* this effect and record the true energy used - watt-hours. (The higher current does cause some losses from wire resistance.)

Power factor measures the difference between real power (watts) and VA. If they are the same the PF = 1.

For an industrial location, with lots of motors, the utility may have a second meter, in addition to the watt-hour meter, that records the "reactive power". The utility would then charge a (big) "penalty" for this "use". For a industrial location, power factor correction makes sense. But it has to be designed for the location. Utilities also do power factor correction with racks of PF correction capacitors.

Since utilities do NOT charge residential users a penalty for "reactive power", there is no advantage to do correction. (There is a trivial reduction in losses from resistance. The losses reduced are only in wires between the utility meter and the "device", likely at the service panel.) And the amount of correction required depends on what is running, which changes.

Claiming large reductions for a residential user is a scam. Literature is often completely deceptive.

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